Comparison of outcomes in ST-elevation myocardial infarction according to age

Background: Myocardial infarction constitutes a significant cause of morbidity and mortality. Its pathophysiology varies according to age; atherosclerosis is the most common cause in older patients while thrombosis or plaque rupture is behind premature MI.

Objective: To compare the outcome differences between young (age ≤ 45 years) and older adults (age > 45 years) presenting with STEMI.

Method: This was a retrospective cohort study of patients presenting with STEMI to the Emergency Department of a tertiary care center, between 2008 and 2018.Cases were patients age ≤ 45 and controls were the older population. Descriptive and bivariate analyses were conducted followed by Logistic regression to identify the outcomes.

Results: 107 cases were matched with 214 controls. Majority of patients were males (93% of cases and controls). Younger patients were more likely to be smokers (80% vs. 57%, p < 0.001) and with a family history of MI (56% vs. 37%, p = 0.002). Diabetes, hypertension, dyslipidemia and a previous history of MI were more common among controls, 37%, 60%, 43% and 42% respectively versus 10%, 24%, 36% and 25% in the younger population. Younger patients had a higher prevalence of single-vessel disease compared to older patients (73% vs. 50%, p = 0.001). LAD was the most commonly blocked vessel in both groups (71% vs. 64% respectively). Ejection fraction was within normal range in the majority of controls and cases (63% vs. 56% respectively and 57% vs. 60% respectively).

Conclusion: Premature MI predominantly affects males and the associated risk factors are smoking and family history of MI. It's characterized by single-vessel disease as compared to older patients.